Wall-type intercom stations of the precedingly characterized type are known from the German utility "model" patent No. 78 07 398 and have the task of providing, in detention and penitentiary facilities, wall-type intercom station as a communications system where an undesired opening or damaging is to be excluded.
The known arrangements for this work used a metal fabricated box that had to be assembled from individual components, with sensor pushbutton switches and signaling contrivances that were imbedded in plastic and were built into the front of the cover plate in order, therewith, to avoid removal.